The Met Police has been criticised for handing over the addresses of 30,000 London gun owners to a third party for a marketing campaign. Gun owners were only made aware their details had been given out after a police campaign leaflet, posted from Leeds, was sent through their letterboxes last month, according to technology website The Register.

The website said the leaflets raised "severe" security implications for the capital's gun owners, which it estimated to be about 5,000 rifle owners and 25,000 shotgun owners.